1. Field of the Invention
The invention concerns a process for recognition of vehicle lane markings from image data, wherein the morphological characteristics of dot-shaped vehicle lane markings are evaluated on the basis of a priori knowledge.
2. Description of the Related Art
Camera based systems for automatic vehicle tracking and for warning of unintentional deviations from the vehicle track or lane depend upon a reliable recognition of the vehicle lane boundaries. Typically, these boundaries are marked by means of continuous or interrupted lines. It is also known (for example: in the USA) to mark vehicle lane boundaries by a sequence of points (terrain points).
In U.S. Pat. No. 5,351,044, a process for recognition of vehicle lane boundaries is disclosed, which evaluates pixel-based image data. Therein, those image points of which the intensity or brightness significantly exceeds the intensity or brightness of the surrounding or ambient points are assigned to a border.
Further, a process is known which evaluates the correlation of the bordering image cells within the image data for detection of the vehicle lane boundaries. For this it is however necessary to transform the perspective camera data into non-perspective image data.
U.S. Pat. Nos. 5,517,412 and 4,868,752 show processes for detection of the vehicle lane boundaries, which are based on the segmentation of linear elements by means of line detectors (“edge detection”) with subsequent Hough-transformation for reconstruction of the boundary. Similar technology is disclosed in U.S. Pat. No. 4,970,653, wherein here the segmentation of the line elements is supported by supplemental template matching.
In the process proposed in U.S. Pat. No. 6,091,833, the area in which linear detection is carried out is curtailed by the selection of areas which, transformed in the frequency space, exhibit a high intensity by their low frequency components.
It is the task of the invention to provide a new process for recognition of vehicle lane markings from image data.